Scanning type image pick-up apparatus and a scanning type laser beam receive apparatus

ABSTRACT

The present invention has an object of realizing highly reliable search with high precision by obtaining a clear view image over a wide view. In particular, a reflection mirror is formed so as to correspond to an image pick-up element at a focus surface of a converging lens of an image pick-up camera and the image pick-up camera is arranged to be capable of freely performing scanning by a scanning mechanism portion. As a result, with the image pick-up camera kept performing linear scanning, the reflection mirror performs triangular scanning in a direction opposite to the scanning direction of the image pick-up camera for every frame cycle T and a light wave taken in by the converging lens is introduced to the image pick-up element for every one frame, thereby to obtain a static view image. The desired object is thus achieved.

BACKGROUND OF THE INVENTION

The present invention relates to a scanning type image pick-up apparatusand a scanning type laser beam receive apparatus suitable for passivelyor actively scanning a wide view-field by a two-dimensional manner.

In general, in this kind of scanning type image pick-up apparatus, animage pick-up camera internally including an image pick-up element of acharge storing type is used to obtain a light wave. In this imagepick-up camera, the image pick-up element has a view angle θ andtherefore, a method of scanning a search range to take in a view imageis adopted in case of searching a wide view.

In the image pick-up camera as described above, the image pick-upelement is provided at a focus position of an optical system, and imagedata is obtained by taking in light waves of a visible region (e.g., 0.4μm to 0.8 μm) and an infrared region (e.g., 3 μm to 12 μm) received bythe optical system and performing photoelectric conversion thereon.Therefore, if an angle range equivalent to an instant view angle of onepixel of the image pick-up element is scanned in one direction at aspeed faster than the speed at which the image pick-up element isexposed, a so-called image flow is caused and the view image obtainedthereby becomes unclear.

Therefore, a conventional scanning type image pick-up apparatus adopts areflection mirror step scanning method in which a reflection mirror isprovided before an image pick-up camera and the reflection mirror isscanned in steps for every unit angle equivalent to a view angle insynchronism with the frame time of the image pick-up element, thereby topick up light waves into an image pick-up element within one frame time(or exposure time) and to obtain a view image, or a camera step scanningmethod in which an image pick-up camera directly performs scanning insteps, thereby to pick up light waves into an image pick-up elementwithin one frame time (or exposure time) and to obtain a view image.

However, if the scanning type image pick-up apparatus as described aboveis constructed so as to have a wide view range, a large reflectionmirror is required from the limitations of the focal distance and theimage pick-up distance, in case of the former method, and an opticalsystem such as a converging lens must be a large size, in case of thelatter method. Thus, in both cases, the apparatus has a very heavyweight. Therefore, in any of these methods, a large driving force isrequired for step scanning, and a time delay occurs when scanning isstarted, so that it is difficult to obtain stable view images.

For example, since a reflection mirror or an image pick-up camera has alarge size and a heavy weight, it is very difficult to perform stepscanning with a high speed of about an image pick-up element framefrequency 60 Hz and a frame cycle 16.7 ms, and therefore, a problemoccurs in that a clear image is difficult to obtain. The same problemoccurs in case of a scanning type laser beam receive apparatus.

BRIEF SUMMARY OF THE INVENTION

As has been explained above, a conventional scanning type image pick-upapparatus has a problem in that it is difficult to obtain a clear viewimage when search over a wide view is realized.

The present invention has been made in view of the above situation, andhas an object of providing a scanning type image pick-up apparatus and alaser beam receive apparatus which obtain a clear view image over a wideview to realize highly reliable search with high precision.

A scanning type image pick-up apparatus comprising: an image pick-upcamera for converging a light wave by a first optical system, changingan optical path of the light wave by a second optical system, and takingin the light wave into a charge storage type image pick-up element,thereby to obtain a view image, the second optical system being arrangedto be capable of freely performing scanning on the image pick-up elementwith the light wave from the first optical system; camera scanning meansfor causing the image pick-up camera to linearly scan a view range,thereby to take in the light wave into the first optical system; andfirst optical system scanning means for causing the second opticalsystem of the image pick-up camera to perform triangular scanning in adirection opposite to a scanning direction of the image pick-up camerafor every frame cycle of the image pick-up camera, thereby to introducethe light wave converged by the first optical system into the imagepick-up element.

A scanning type image pick-up apparatus comprising: an image pick-upcamera for converging a light wave by a first optical system, changingan optical path of the light wave by a second optical system, and takingin the light wave into a charge storage type image pick-up element,thereby to obtain a view image, the second optical system being arrangedto be capable of freely performing scanning so as to correspond to thefirst optical system and the image pick-up element; camera scanningmeans for causing the image pick-up camera to linearly scan a viewrange, thereby to take in the light wave into the first optical system;and a rotation mechanism for rotating the second optical system of theimage pick-up camera around an optical axis by an angle decided byscanning angle speeds in two axial directions of the two-dimensionalscanning means and around an axis parallel to an incidence surface ofthe image pick-up element at an angle speed decided by scanning anglespeeds in the two axial directions of the two-dimensional scanningmeans.

In addition, a scanning type laser beam receive apparatus comprising: alaser radar for converging a laser beam by a first optical system, forchanging an optical path of the laser beam by a second optical system,and for taking in the laser beam into a laser beam receiver, thereby toobtain a view image, the second optical system being arranged to becapable of freely performing scanning so as to correspond to the firstoptical system and the laser beam receiver; and two-dimensional scanningmeans for causing the laser radar to linearly scan a view range, therebyto take in the laser beam into the first optical system, characterizedin that the second optical system of the laser radar includes amechanism which rotates the second optical system around an optical axisby an angle decided by scanning angle speed in two axial directions ofthe two-dimensional scanning means and around an axis parallel to alight receive surface of the laser beam receiver at an angle speeddecided by scanning angle speeds in the two axial directions of thetwo-dimensional scanning means.

Another a scanning type image pick-up apparatus characterized bycomprising: an image pick-up camera for converging a light wave by afirst optical system, for changing an optical path of the light wave bya second optical system, and for taking in the light wave into a chargestorage type image pick-up element, thereby to obtain a view image, thesecond optical system being arranged to be capable of freely performingscanning with use of an electro-optical deflector capable ofelectrically deflecting the light wave so as to correspond to the firstoptical system and the image pick-up element; scanning means for causingthe image pick-up camera to linearly scan a view range, thereby to takein the light wave into the first optical system; and deflector drivemeans for causing the electro-optical deflector to deflect an opticalaxis at an angle decided by a scanning angle speed of the scanningmeans.

Or, another a scanning type image pick-up apparatus characterized bycomprising: an image pick-up camera for converging a light wave by afirst optical system, for changing an optical path of the light wave bya second optical system, and for taking in the light wave into a chargestorage type image pick-up element, thereby to obtain a view image, thesecond optical system being arranged to be capable of freely performingscanning in a two-dimensional direction with use of first and secondelectro-optical deflectors respectively capable of electricallydeflecting the light wave in directions perpendicular to each other soas to correspond to the first optical system and the image pick-upelement; two-dimensional scanning means for causing the image pick-upcamera to linearly scan a view range, thereby to take in the light waveinto the first optical system; first deflector drive means for causingthe first electro-optical deflector to deflect an optical axis at anangle decided by a scanning angle speed of the two-dimensional scanningmeans in a first axial direction thereof; and second deflector drivemeans for causing the second electro-optical deflector to deflect anoptical axis at an angle decided by a scanning angle speed of thetwo-dimensional scanning means in a second axial direction thereofperpendicular to the first axial direction.

Or, another a scanning type image pick-up apparatus characterized bycomprising: an image pick-up camera for converging a light wave by afirst optical system, for changing an optical path of the light wave bya second optical system, and for taking in the light wave into a chargestorage type image pick-up element, thereby to obtain a view image, thesecond optical system being arranged to be capable of freely performingscanning in a two-dimensional direction with use of an electro-opticaldeflector capable of electrically deflecting the light wave so as tocorrespond to the first optical system and the image pick-up element andwith use of a rotation mechanism for rotating the electro-opticaldeflector around an optical axis; two-dimensional scanning means forcausing the image pick-up camera to linearly scan a view range, therebyto take in the light wave into the first optical system; and deflectordrive means for rotating the electro-optical deflector around an opticalaxis by an angle decided by scanning angle speeds of the two-dimensionalscanning means in two axial directions thereof, with respect to therotation mechanism of the image pick-up camera, and for causing theelectro-optical deflector to deflect an optical axis around an axisparallel to a surface of the image pick-up element at an angle speeddecided by the scanning angle speeds of the two-dimensional scanningmeans in the two axial directions thereof.

Another a scanning type laser beam receive apparatus characterized bycomprising: a laser radar for converging a laser beam by a first opticalsystem, for changing an optical path of the laser beam by a secondoptical system, and for taking in the laser beam into a laser beamreceiver, thereby to obtain a view image, the second optical systembeing arranged to be capable of freely performing scanning with use ofan electro-optical deflector capable of electrically deflecting thelaser beam so as to correspond to the first optical system and the laserbeam receiver; scanning means for causing the laser radar to linearlyscan a view range, thereby to take in the laser beam into the firstoptical system; and deflector drive means for causing theelectro-optical deflector to deflect an optical axis at an angle decidedby a scanning angle speed of the scanning means.

Or, another a scanning type laser beam receive apparatus characterizedby comprising: a laser radar for converging a laser beam by a firstoptical system, for changing an optical path of the laser beam by asecond optical system, and for taking in the laser beam into a laserbeam receiver, thereby to obtain a view image, the second optical systembeing arranged to be capable of freely performing scanning in atwo-dimensional direction with use of first and second electro-opticaldeflectors respectively capable of electrically deflecting the laserbeam in directions perpendicular to each other so as to correspond tothe first optical system and the laser beam receiver;

two-dimensional scanning means for causing the laser radar to linearlyscan a view range, thereby to take in the laser beam into the firstoptical system; first deflector drive means for causing the firstelectro-optical deflector to deflect an optical axis at an angle decidedby a scanning angle speed of the two-dimensional scanning means in afirst axial direction thereof; and second deflector drive means forcausing the second electro-optical deflector to deflect an optical axisat an angle decided by a scanning angle speed of the two-dimensionalscanning means in a second: axial direction thereof perpendicular to thefirst axial direction.

Or another a scanning type laser beam receive apparatus characterized bycomprising: a laser radar for converging a light wave by a first opticalsystem, for changing an optical path of the laser beam by a secondoptical system, and for taking in the laser beam into a laser beamreceiver, thereby to obtain a view image, the second optical systembeing arranged to be capable of freely performing scanning in atwo-dimensional direction with use of an electro-optical deflectorcapable of electrically deflecting the laser beam so as to correspond tothe first optical system and the laser beam receiver and with use of arotation mechanism for rotating the electro-optical deflector around anoptical axis; two-dimensional scanning means for causing the laser radarto linearly scan a view range, thereby to take in the laser beam intothe first optical system; and deflector drive means for rotating theelectro-optical deflector around an optical axis by an angle decided byscanning angle speeds of the two-dimensional scanning means in two axialdirections thereof, with respect to the rotation mechanism of the laserradar, and for causing the electro-optical deflector to deflect anoptical axis around an axis parallel to a surface of the laser radar atan angle speed decided by the scanning angle speeds of thetwo-dimensional scanning means in the two axial directions thereof.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a block diagram showing a basic structure of a scanning typeimage pick-up apparatus adopting the present invention.

FIG. 2 is a perspective view showing a specific structure of areflection mirror rotation mechanism used for the scanning apparatusshown in FIG. 1.

FIGS. 3A to 3F are timing charts showing timing waveforms for explainingoperation of the scanning type image pick-up apparatus shown in FIG. 1.

FIG. 4 is a block diagram showing a structure of a first embodiment of ascanning type image pick-up apparatus according to the presentinvention.

FIG. 5 is a perspective view showing a specific structure of areflection mirror rotation mechanism used in the embodiment.

FIG. 6 is a block diagram showing a structure of a second embodiment ofa scanning type image pick-up apparatus according to the presentinvention.

FIGS. 7A to 7E are timing charts showing relation-ships of controltimings between scanning angles, light deflection angles, and the likeof the second embodiment.

FIG. 8 is a block diagram showing a structure of a third embodiment of ascanning type image pick-up apparatus according to the presentinvention.

FIG. 9 is a block diagram showing a structure of a fourth embodiment ofa scanning type image pick-up apparatus according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

In the following, embodiments of the present invention will be explainedwith reference to the drawings.

Firstly, the basic structure of a scanning type image pick-up apparatusaccording to the present invention will be explained with reference toFIG. 1.

In FIG. 1, an image pick-up camera 10 for picking up light waves ismounted on a scanning mechanism portion 11 and is arranged to be capableof freely scanning one axial direction (e.g., azimuth direction) by thescanning mechanism portion 11. The light waves are those included in avisible region described above (e.g., 0.4 μm to 0.8 μm) and an infraredregion (e.g., 3 μm to 12 μm).

The scanning mechanism portion 11 described above comprises a torquer 11a and a gimbal mechanism 11 b. The scanning mechanism portion 11 has aninput end connected with an output end of an adder 12 through a servoamplifier 13. The adder 12 has a minus input end connected with anoutput end of an angle sensor 14 and is inputted with a scanning anglesignal of the scanning mechanism portion 11 through the angle sensor 14.Further, the adder 12 has a plus input end connected with a camerascanning command signal output end of a scanning command signalgenerator portion 15.

Specifically, the adder 12 generates a camera drive signal by obtaininga difference between a camera scanning command signal (i.e., a signalfor instructing a scanning angle of an image pick-up camera 10)outputted from the scanning command generator portion 15 and an actualscanning angle signal from an angle sensor 14, and outputs the cameradrive signal to the scanning mechanism portion 11 through the servoamplifier 13. The scanning mechanism portion 11 controls the scanningangle φ of the image pick-up camera 10 to be linear on the basis of thecamera drive signal inputted (ref. FIG. 3).

The image pick-up camera 10 is constructed as a combination of aconverging lens 10 a, a reflection mirror 10 b, and a charge storagetype image pick-up element 10 c having a view angle θ. A light wavepicked up is converged by the converging lens 10 a and the light wavethus converged is imaged on the image pick-up element 10 c through thereflection mirror 10 b, thus obtaining a static view image.

Here, the reflection mirror 10 b is provided to be capable of freelyperforming triangular scanning in a camera scanning direction by amirror scanning drive portion 17 in correspondence with the focusingsurface of the converging lens 10 a, and the light wave converged by theconverging lens 10 a is imaged on the image pick-up element 10 c. Thereflection mirror 10 b is equipped with an angle sensor 18, and anoutput end of the angle sensor 18 is connected with a minus input end ofan adder 19. A plus input end of the adder 19 is connected with a mirrorscanning command signal output end of the scanning command signalgenerator portion 15.

Specifically, the adder 19 generates a mirror drive signal by obtaininga difference between a mirror scanning command signal (or a signal forinstructing a triangular scanning angle of the reflection mirror 10 b)from the scanning command signal generator portion 15 and an actualmirror angle signal from the angle sensor 18, and outputs the mirrordrive signal through a servo amplifier 20 to the mirror scanningmechanism portion 17 described above. The mirror scanning mechanismportion 17 causes the reflection mirror 10 b to perform triangularscanning or so-called swing scanning in the direction opposite to thecamera scanning direction, on the basis of the mirror drive signalinputted (ref. FIG. 3B).

Here, a light wave enters into the image pick-up element 10 c at anincidence angle Δφ (ref. FIGS. 3C and 3D), and a desired view angle θ ismaintained. Simultaneously, the image pick-up element 10 c is controlledby a synchronous trigger for every frame cycle T, and exposure of anoptical image and charge reading operation are carried out (ref. FIGS.3E and 3F), so that a static view image is obtained.

The scanning command signal generator portion 15 generates a camerascanning command signal for causing the image pick-up camera 10 toperform scanning and a mirror scanning command signal for causing thereflection mirror 10 b to perform scanning, on the basis of a commandsignal not shown, as described above.

In the structure as described above, for example, where the view angle θis set to 3° and the frame frequency and the frame cycle are 60 Hz and T(1/60) s (1.67 ms), the scanning command signal generator portion 15generates such a camera scanning command signal which causes the imagepick-up camera 10 to scan one direction (e.g., the azimuth direction) atan angle speed of 3°/({fraction (1/60)})=180° and the portion 15 outputsthe camera scanning command signal to the adder 12. The adder obtains adifference between the camera scanning command signal and a camera anglesignal from an angle sensor 14, to generates a camera drive signal, andcontrols and drives a scanning mechanism portion 11 through a servoamplifier 13. In this manner, the image pick-up camera 10 is controlledso as to scan one direction (e.g., the azimuth direction) at an anglespeed of 3°/({fraction (1/60)})=180° within a view, and light waves arepicked up by a converging lens 10 a.

Simultaneously, the scanning command signal generator portion 15generates a mirror scanning command signal which causes the reflection10 b of the image pick-up camera 10 to perform triangular scanning in adirection opposite to the camera scanning direction at an angle speed of½ of 180°/s in synchronism with a synchronous trigger of a frame cycle Tof the image approximately for every {fraction (1/60)}s (e.g., 16 ms),and outputs the mirror scanning command signal to the adder 19. Theadder obtains a difference between the scanning command signal and amirror angle signal from the angle sensor 18, to generate a mirror drivesignal, and controls and drives the mirror scanning mechanism portion 17through the servo amplifier 20. In this manner, the reflection mirror 10b performs triangular scanning at an angle speed of ½ of 180° in thedirection opposite to the camera scanning direction in synchronism witha synchronous trigger of a frame cycle T of the image pick-up element 10c approximately for every {fraction (1/60)}s (e.g., 16 ms), and lightwaves converged by the converging lens 10 a are introduced at anincidence angle Δφ, to form an image.

The image pick-up element 10 c maintains a desired exposure time Ta sothat a desired charge reading time Tb is maintained thereby to attain astatic view image at a view angle θ.

In case of scanning a direction substantially perpendicular to thescanning direction on condition that the image pick-up camera 10 hascompleted scanning in one direction, for example, the image pick-upcamera 10 together with the scanning mechanism portion 11 is caused toscan this direction and the image pick-up camera 10 and the reflectionmirror 10 b repeat scanning in the same manner as described above,thereby to obtain a static view image. The time at which scanning isperformed in the direction substantially perpendicular to the scanningdirection is set within the charge reading time Tb.

Thus, the image pick-up apparatus described above is arranged such thatthe reflection mirror 10 b is formed on the focus plane of theconverging lens 10 a of the image pick-up camera 10 so as to freelyperform scanning in correspondence with the image pick-up element 10 cand such that the image pick-up camera 10 is arranged so as to freelyperform scanning through the image pick-up camera 10. In this manner,with the image pick-up camera 10 kept performing linear scanning, thereflection mirror 10 b is caused to perform triangular scanning thedirection opposite to the scanning direction of the image pick-up camera1 for every frame cycle T of the image pick-up element 10 c, and lightwaves picked up by the converging lens 10 a are introduced into theimage pick-up element 10 c for every frame, thereby to obtain a staticview image.

As a result, since only the reflection mirror 10 b having a relativelysmall size enough to take in an image formed on the focus plane of theconverging lens 10 a into the image pick-up element 10 c needs toperform scanning in correspondence with the image pick-up camera 10,secure operation control for obtaining image data can be easily realizedwithin a view angle of the image pick-up element 10. Therefore, a clearprecise static image can be securely obtained within a wide view pickedup by the image pick-up camera 10.

In addition, in this manner, as the sensitivity of the image pick-upelement 10 is raised to be high, it is possible to obtain a clear staticview image which match with such a high sensitivity. Therefore,sensitivity performance of the image pick-up element 10 can beeffectively used.

Note that the above embodiment describes a case in which the imagepick-up camera 10 is arranged so as to freely scan one axial directionwith use of the scanning mechanism portion 11. However, the scanningmechanism portion 11 may be constructed so as to scan two axialdirections substantially perpendicular to each other, e.g., the azimuthdirection and the elevation direction, and the image pick-up camera 10itself may be constructed so as to scan two directions substantiallyperpendicular to each other.

Further, the above embodiment has been explained as a case in which thereflection mirror 10 b is provided in the image pick-up camera 10 so asto perform scanning freely and light waves converged by the converginglens 10 a are reflected by the reflection mirror 10 b so as to form anoptical image on the image pick-up camera 10. However, an optical phasemember such as an optical phase shifter or the like which makes lightwaves passing and set in a phase may be provided on the focus plane ofthe converging lens 10 a, and light waves converged by the converginglens 10 a may be introduced to the image pick-up element 10 c throughthe optical phase member. In this case, substantially, the same effectsas obtained in the above embodiment can be expected.

In the structure shown in FIG. 1, the rotation (or swing) shaft of thereflection mirror 10 b for restricting an image flow must be set inparallel with one scanning axis of the entire image pick-up camera 10,and therefore, operation of restricting an image flow cannot beperformed in the other direction. For example, this means that the axisof the reflection mirror 10 b is set in parallel with one of twoscanning axes when two axes of a horizontal direction and a verticaldirection are adopted for search scanning, and the scanning directionvertical to the axis of the reflection mirror 10 b is the main scanningdirection. For example, when search scanning is performed in anobliquely upward direction, horizontal components of an image flow canbe restricted and vertical components of an image flow cannot berestricted. This is a main problem to be solved by the presentinvention.

FIG. 4 shows a structure of a first embodiment of a scanning type imagepick-up apparatus according to the present invention. Note that thosecomponents of FIG. 4 which are the same as those of FIG. 1 are referredto by the same reference symbols and only those components of FIG. 4which are different from those of FIG. 1 will now be described in detailbelow.

In FIG. 4, an image pick-up camera 10 is mounted on a scanning mechanismportion 11 and is caused to scan an arbitrary direction decided bysynthesizing two-dimensional directions (e.g., the horizontal directionand the vertical direction) by the scanning mechanism portion 11.

The scanning mechanism portion 11 is equipped with an angle sensor (orangle speed sensor) 14 and a servo amplifier 13 with respect to two axesto be scanned. An image pick-up camera is caused to scan arbitraryvertical and horizontal directions by a camera scanning command signalfrom a scanning command signal generator portion 15 to an adder 12.

Meanwhile, the image pick-up camera 10 introduces light waves passingthrough a converging lens 10 a, to a reflection mirror 10 b. Thereflection mirror 10 b is equipped with an angle sensor 18 and a mirrorscanning mechanism portion 17 which is caused to perform scanning (i.e.,reverse scanning) in a direction opposite to the scanning direction ofthe image pick-up camera 10. The scanning command signal generatorportion 15 supplies a signal to the adder 19, thereby to drive themirror scanning mechanism portion 17. The scanning command signalgenerator portion 15 takes in an angle and an angle speed from the anglesensor 14, to control the angle of reverse scanning and the angle of theaxis.

Further, the reflection mirror 10 b is provided with a rotationmechanism 21 around an optical axis and an angle sensor 22, togetherwith the mirror scanning drive portion 17 and the angle sensor 18.Specifically, the rotation mechanism 21 is constructed by rotatablyfixing a scanning drive shaft to a ring 211 and by rotating the ring 211by rotating a motor 213 through a transmission member 212 such as a gearor the like. In this case, the angle sensor 22 may be equipped on therotation shaft of the motor 213. In this manner, the reflection mirror10 b is capable of changing the axis of the reverse scanning on thebasis of a signal from the scanning command signal generator portion 15,like triangular scanning.

Specifically, a command signal for instructing a mirror scanning angleoutputted from the scanning command signal generator portion 15 isconverted into a drive signal by a servo amplifier 23, and the rotationmechanism 21 is driven on the basis of the drive signal. When thereverse scanning axis of the reflection mirror 10 b is inclined as aresult, the inclination angle is detected by an angle sensor 22 and isinputted to a minus input end of an adder 24. The adder 24 carries out asubtraction by reducing an output angle of the angle sensor 22 from anangle specified by the mirror scanning command signal inputted to a plusinput end of this adder. In this manner, the reverse scanning axis ofthe reflection mirror 10 b is set to an inclination angle correspondingto the command signal.

Examples of calculating an angle by which the scanning axis of thereflection mirror 10 b should be rotated and an angle speed of thereverse scanning will be described below. For example, where thescanning directions of the image pick-up camera 10 are the horizontaland vertical directions and the reference scanning direction of thereflection mirror 10 b is the horizontal direction, the angle by whichthe scanning axis of the reflection mirror 10 b should be rotated isexpressed as follows.

θ=tan⁻¹ (ωv/ωh)

The angle speed of the reverse scanning is expressed as follows.

ω={square root over (ωv ² +ωh ²+L )}

Here, ωv is a scanning angle speed in a vertical direction and ωh is ascanning angle speed in a horizontal direction.

Note that it is apparent that refraction depending on a parallel opticalplate may be used although a reflection mirror 10 b is shown in thepresent embodiment. In addition, although frequencies of light waves arenot limited, it is apparent that the present invention is applicable tooverall light waves including ultraviolet light waves, visible lightwaves, infrared light waves, and the like. Further, in case of applyingthe present invention to a scanning type laser beam receive apparatus,the image pick-up camera 10 may be replaced with a laser radar. In thiscase, a laser beam receiver may be used in place of the image pick-upelement 10 c.

In the structure of the embodiment described above, it is necessary todrive mechanically the reflection mirror, mechanical limitations cannotbe avoided, e.g., the adjustable scanning angle speed is limited and theadjustable direction is limited to only one direction. In the followingembodiment, this problem will be solved.

FIG. 6 shows a structure of a second embodiment of a scanning imagepick-up apparatus according to the present invention. In FIG. 6, animage pick-up camera 31 for taking in a light wave is mounted on ascanning mechanism portion 35 and is provided so as to freely scan oneaxial direction (e.g., an azimuth direction) through the scanningmechanism portion 35. A sensor portion 36 is provided on the scanningaxis. The light waves adopted are those in a visible region (e.g., arange of 0.4 μm to 0.8 μm) and an infrared region (e.g., a range of 3 μmto 12 μm).

The above scanning mechanism portion 35 comprises a torquer and a gimbalmechanism and has an input end connected with an output end of an adder38 through a servo amplifier 37. The adder 38 has a plus input endconnected with a camera scanning command signal output end of a scanningcommand signal generator portion 39.

Specifically, the adder 38 generates a camera drive signal by obtaininga difference between a camera scanning command signal (e.g., a signalfor instructing a scanning angle of the image pick-up camera 31)outputted from the scanning command signal generator portion 39 and anactual scanning angle signal from the sensor portion 36, and outputs thecamera drive signal to the scanning mechanism portion 35. The scanningmechanism portion 35 controls the scanning angle φ of the image pick-upcamera 31 on the basis of a camera drive signal inputted, such thatscanning is performed linearly (ref. FIG. 7A).

The image pick-up camera 31 is constructed by arranging a converginglens 32, an electro-optical deflector 34 a, and a charge storage typeimage pick-up element 33 having a view angle θ on an optical axis. Lightwaves picked up are converged by the converging lens 32 and theconverged light waves are imaged on the image pick-up element 33 throughthe electro-optical deflector 34 a, thereby to obtain a static viewimage.

Here, the electro-optical deflector 34 a has a structure in which aplurality of prisms made of electro-optical crystal having a so-calledelectro-optical effect that the refraction factor is changed by applyingan electric field are adhered on each other such that optical axes ofthe prisms are inverted one another. When a light wave enters into thedeflector 34 a applied with a uniform electric field, the light wave isdeflected and injected out. The deflection amount can be expressed inform of a function concerning an applied electric field. This means thatthe deflection amount can be controlled by an applied voltage.

In this apparatus, therefore, the angle speed in a scanning directionobtained by the sensor portion 36 is inputted into a deflector controlsignal generator portion 42, thereby to generates a control signal (orangle command signal) corresponding to a return angle equivalent to anangle movement amount. The control signal is converted into a drivevoltage by the servo amplifier 40 a through the adder 41 a and issupplied to the electro-optical deflector 34 a. A voltage change causedby deflection by the electro-optical deflector 34 a is returned andinputted into the adder 41 a, thereby to perform deflectioncorresponding to an angle specified by the control signal.

Where the frame cycle T, exposure time Ta, and charge reading time Tb ofthe image pick-up element 33 are set as shown in FIG. 6E, the opticaldeflection angle can be returned in the reverse direction by an angleequivalent to a scanning angle at the frame cycle, as shown in FIG. 7D,when a synchronous trigger corresponding to the frame cycle T issupplied to the deflector control signal generator portion 42 at atiming shown in FIG. 7D. Therefore, the light movement angle on thefocus plane of the image pick-up element 33 is constant at the portionof the exposure time Ta, as shown in FIG. 7C, and a static image isthereby obtained, so that a function equivalent to rotation control of areflection mirror as described before can be realized.

Thus, according to the structure of the present embodiment, an anglespeed detection output from the sensor portion 36 set on a scanning axis(or rotation axis) is used as a feed back signal to the electro-opticaldeflector 34 a, and therefore, a return angle equivalent to an anglemovement amount depending on scanning by the image pick-up camera 31 canbe supplied to the electro-optical deflector 34 a. Specifically, animage flow caused by scanning can be equivalently restricted and animage during an exposure time can be stopped statically.

Also in the present embodiment, the image pick-up camera 31 may bereplaced with a laser radar and a laser beam receiver may be used inplace of the image pick-up element in case of applying the presentinvention to a scanning type laser beam receive apparatus.

Although an image flow only in the horizontal direction or the verticaldirection can be prevented by using one electro-optical deflector, asdescribed above, prevention of an image flow in case of simultaneousscanning (or two-dimensional scanning) in both the horizontal andvertical directions can be realized by the following third and fourthembodiments.

FIG. 8 shows a structure of a third embodiment of a scanning type imagepick-up apparatus according to the present invention. Note that thosecomponents of FIG. 8 which are the same as those of FIG. 6 are referredto by the same reference symbols and only those portions which aredifferent from those of FIG. 6 will be specifically described below.

The scanning mechanism portion 35 according to the present embodimentcauses an image pick-up camera 31 to scan two-dimensional directions(which are a horizontal direction and a vertical direction, for example)and a sensor portion 36 detects a scanning angle in each of thedirections.

Meanwhile, the image pick-up camera 31 is constructed by arranging aconverging lens 32, a first electro-optical deflector 34 a, a secondelectro-optical deflector 34 b, and a charge storage type image pick-upelement 33 on an optical axis. Light waves taken in are converged by theconverging lens 32. The light waves converged are deflected in adirection opposite to the horizontal scanning direction by the firstelectro-optical deflector 34 a and are deflected in a direction oppositeto the vertical scanning direction by the second electro-opticaldeflector 34 b. Thereafter, the light waves are imaged on the imagepick-up element 33, thereby to obtain a static view image.

In this case, a deflector control signal generator portion 42 controlsthe first electro-optical deflector 34 a so as to perform deflection ina direction opposite to the horizontal scanning direction at an equalangle speed through an adder 41 a and a servo amplifier 40 a, and alsocontrols the second electro-optical deflector 34 b so as to performdeflection in a direction opposite to the vertical scanning directionthrough an adder 41 b and a servo amplifier 40 b.

As is apparent from the above, the scanning type image pick-up apparatusaccording to the present embodiment has an independent electro-opticaldeflector for each of the horizontal and vertical directions, so thatcorrections can independently made in both the horizontal and verticaldirections. Therefore, an image flow can be restricted independently inboth the horizontal and vertical directions by independently feedingback the angle speeds in the horizontal and vertical directions to theelectro-optical deflectors 34 a and 34 b.

FIG. 9 shows a structure of a fourth embodiment of a scanning type imagepick-up apparatus according to the present invention. Note that thosecomponents which are the same as those of FIG. 6 are referred to by thesame reference symbols and only those components which are differentfrom those of FIG. 6 will be specifically described below.

A scanning mechanism portion 35 causes an image pick-up camera 31 toscan two-dimensional directions (which are a horizontal direction and avertical direction, for example) like in the third embodiment, and asensor portion 36 detects a synthesis scanning angle speed concerningboth of the directions.

Meanwhile, the image pick-up camera 31 is constructed by arranging aconverging lens 32, an electro-optical deflector 34 a, and a chargestorage type image pick-up element 33 on an optical axis and byproviding a rotation mechanism 44 for rotating the electro-opticaldeflector 34 around the optical axis. Light waves taken in are convergedby the converging lens 32 and the light waves thus converged aredeflected in a direction opposite to the scanning direction by theelectro-optical deflector 34 a. The light waves are thereafter imaged onthe image pick-up element 33, thereby to obtain a static view image.

In this case, a deflector rotation signal generator portion 43, an adder41 c, and a servo amplifier 40 c are provided for control and drive therotation mechanism 44. The deflector rotation signal generator portion43 drives the rotation mechanism 44 through the adder 41 c and the servoamplifier 40 c on the basis of synthesis angle speed data from thesensor portion 36, thereby to cause the deflection direction of thefirst electro-optical deflector 34 b to correspond to the scanningdirection, and the deflector control signal generator portion 42controls the electro-optical deflector 34 a so as to perform deflectionin a direction opposite to the scanning direction at an equal anglespeed through the. adder 41 a and the servo amplifier 40 a.

As is apparent from the above, the scanning type image pick-up apparatusaccording to the present embodiment has an electro-optical deflector 34a which is freely rotatable around an optical axis and theelectro-optical deflector 34 a is rotated and controlled such that themoving direction of an image corresponds to the deflection direction oflight waves. Specifically, the angle speeds in the horizontal andvertical directions are synthesized with each other thereby to obtainthe scanning direction and the scanning angle speed of the image pick-upcamera 31. The signal concerning the scanning direction is fed back tocontrol rotation of the electro-optical deflector 34 a around theoptical axis and the signal concerning the scanning angle speed is fedback to control the deflection amount of light waves. Therefore, animage flow can be restricted both in the horizontal direction and thevertical direction.

As described above, according to the structures of the third and fourthembodiments, a scanning type image pick-up apparatus can realizerestriction of an image flow without use of a mechanical operatingportion. In addition, it is possible to realize a scanning type imagepick-up apparatus whose scanning direction is not limited to onedirection.

Further, since not only the deflection amount but also the deflectiondirection can be controlled electrically, it is possible to carry outeasily such control which has been difficult to realize by a mechanicalmeans, e.g., inversion of the phase in accordance with inversion of therotation direction by reciprocal scanning.

Note that the image pick-up camera 31 may be replaced with a laser radarand a laser beam receiver may be used in place of the image pick-upelement 10 c in case of applying the third or fourth embodiments to ascanning type laser beam receive apparatus.

As has been specifically described above, according to the presentinvention, it is possible to provide a scanning type image pick-upapparatus and a scanning type laser beam receive apparatus which arecapable of obtaining a clear view image over a wide view field andrealize highly reliable search with high precision.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. A scanning type image pick-up apparatuscomprising: an image pick-up camera including (1) a first optical systemfor condensing a light wave, (ii) a second optical system for changingan optical path of the light wave condensed by the first optical system,(iii) a charge storage type image pick-up element for receiving thelight wave the optical path of which is changed by the second opticalsystem, and performing optical/electrical conversion on the light wave,thereby to obtain a view image, (iv) a first rotating mechanism forrotating the second optical system to scan the light wave over the imagepick-up element, and (v) a second rotating mechanism for rotating arotation axis of the first rotating mechanism around a rotation axis ofthe first optical system, thereby to change an angle at which the lightwave is scanned; camera scanning means for causing the image pick-upcamera to linearly scan a view range in a reference direction andshifting a scanning axis along which the image pick-up camera linearlyscans the view range such that the scanning axis is perpendicular to thereference direction, thereby to perform two-dimensional scanning; anglespeed detecting means for detecting scanning angle speeds in thereference direction and a direction perpendicular thereto: and acontroller for controlling driving of the first and second rotatingmechanisms of the image pick-up camera based on the scanning anglespeeds detected by the angle detecting means, such that the secondoptical system causes the light wave to perform reverse scanning inassociation with the two-directional scanning of the camera scanningmeans.
 2. A scanning type image pick-up apparatus according to claim 1,wherein the second optical system is provided so as to correspond to afocus plane of the first optical system.
 3. A scanning type imagepick-up apparatus according to claim 1, wherein the camera scanningmeans causes the image pick-up camera to scan two axial directionssubstantially perpendicular to each other.
 4. A scanning type imagepick-up apparatus according to one of claims 1, wherein the secondoptical system of the image pick-up camera comprises a reflection mirrorfor reflecting the light wave.
 5. A scanning type image pick-upapparatus according to one of claims 1, wherein the second opticalsystem of the image pick-up camera comprises an optical phase memberwhich allows the light wave to pass.
 6. A scanning type laser beamreceive apparatus comprising: a laser radar for converging a laser beamby a first optical system, for changing an optical path of the laserbeam by a second optical system, and for taking in the laser beam into alaser beam receiver, thereby to obtain a view image, the second opticalsystem being arranged to be capable of freely performing scanning so asto correspond to the first optical system and the laser beam receiver;and two-dimensional scanning means for causing the laser radar tolinearly scan a view range, thereby to take in the laser beam into thefirst optical system, Wherein the second optical system of the laserradar includes a mechanism which rotates the second optical systemaround an optical axis by an angle decided by scanning angle speed intwo axial directions of the two-dimensional scanning means and around anaxis parallel to a light receive surface of the laser beam receiver atan angle speed decided by scanning angle speeds in the two axialdirections of the two-dimensional scanning means.
 7. A scanning typelaser beam receive apparatus according to claim 6, wherein the secondoptical system is provided so as to correspond to a focus plane of thefirst optical system.
 8. A scanning type laser beam receive apparatusaccording to claim 6, wherein the two-dimensional scanning means takesin the laser beam by causing the laser radar to scan two axialdirections substantially perpendicular to each other.
 9. A scanning typelaser beam receive apparatus according to one of claim 6, wherein thesecond optical system of the laser radar is constituted by a reflectionmirror for reflecting the laser beam.
 10. A scanning type laser beamreceive apparatus according to one of claim 6, wherein the secondoptical system of the laser radar is constituted by an optical phasemember which allows the laser beam to pass.